Breast cancer is the most commonly diagnosed female cancer, causing almost 25% of cancers in women in the United States.
It is the second leading cause of cancer deaths, behind lung cancer, but is the most common cancer death in women aged 20 to 59 years.
The overall lifetime risk of breast cancer in American women is 1 in 8. There are a multitude of genetic, hormonal and environmental risk factors for breast cancer. However, screening of ALL women is critical, as up to 50% of women diagnosed with breast cancer have no identifiable risk factors except female gender and increasing age.
Because recommended screening is frequently followed, most women diagnosed with breast cancer are asymptomatic. The tumor is simply found incidentally on physical examination or screening mammography.
Common Signs and Symptoms
The most common presentation of breast cancer is a solitary mass in one breast. It is generally:
- Hard
- Irregular in shape
- Non-mobile
- May or may not be painful
- Persists for more than one menstrual cycle (in premenopausal women)
Other Signs and Symptoms
Other signs and symptoms of breast cancer occur primarily in women with systemic disease spread. This may be at the time of diagnosis (less than 10% of patients) or more commonly, at the time of disease recurrence:
- Fatigue due to anemia of chronic disease
- Bone pain and/or fractures, due to metastasis (spread) to the bone
- Abdominal pain and swelling, due to liver involvement
- Respiratory symptoms, such as shortness of breath, due to lung involvement
- Headaches, seizures or stroke-like symptoms, due to central nervous system (CNS) metastases
Associated Disorders
LYMPHEDEMA
Lymphedema results when there is blocked drainage of lymphatics in a part of the body, most commonly the extremities (arms and legs). Lymph nodes collect and filter extracellular fluid. If lymph nodes are blocked or removed, fluid will accumulate in that area and cause swelling and pain. In breast cancer, lymphedema is a common complication following removal of the axillary lymph nodes, which is done as part of staging. The increased use of sentinel lymph node biopsies spares many women from this complication. However, it is still experienced frequently. In addition to pain, sensory nerve loss, recurrent infections, and skin ulcers may occur in the area of lymphedema.
Treatments for lymphedema include:
- Skin care with thorough cleansing and moisturizing, to minimize the risk of infection
- Direct lymphatic massage
- Elastic compression garments, which maintain any edema reduction achieved with massage
- Sequential gradient pumps, which gently move the lymph fluid out of the affected area
HYPERCALCEMIA OF MALIGNANCY
Hypercalcemia of malignancy (HCM) is the most common life-threatening metabolic disorder in oncology, affecting 10 to 25% of all cancer patients. Different tumors have very different incidences of HCM, and degree of HCM does NOT always correlate with extent of disease. The highest incidences are in breast cancer (25% overall; 75% in patients with bone metastases), as well as lung cancer and multiple myeloma.
HCM is a problem, because a precise calcium range needs to be maintained in the blood. Calcium is of course needed for the skeleton, but it also stabilizes cell membranes and is involved in muscle contractions (including the heart muscle). The skeleton accounts for 99% of total body calcium. Bone remodeling is an ongoing process that consists of bone break down by osteoclasts and bone formation by osteoblasts. Disruption of this process can lead to increased calcium concentrations in the blood.
In breast cancer, two factors contribute to HCM. First, the tumor cells release substances that promote break down of bone. The most important of these is parathyroid hormone-related protein (PTH-rp). PTH-rp can be measured in the blood and is elevated in 80% of cancer patients with HCM. In addition, bone metastases lead to local invasion of bone, with subsequent release of calcium into the bloodstream.
The use of preventative bisphosphonate therapy (see Treatment Options) in breast cancer patients with bone metastases has significantly decreased the incidence of HCM in recent years. When it occurs, signs and symptoms include nausea/vomiting, constipation, increased urination, and fatigue. Very high, untreated calcium levels can lead to coma and cardiac arrest. Treatment of HCM involves brisk intravenous hydration and administration of a bisphosphonate drug, such as pamidronate or zoledronic acid.
